Re^2: Understanding a portion on the Perlretut


Do you know where your variables are?
	PerlMonks

Re^2: Understanding a portion on the Perlretut

by BlueStarry (Novice)

on Dec 09, 2015 at 13:26 UTC ( [id://1149756]=note: print w/replies, xml )

Need Help??

in reply to Re: Understanding a portion on the Perlretut
in thread Understanding a portion on the Perlretut

There is no such sentence on the explanation.

Comment on Re^2: Understanding a portion on the Perlretut

Replies are listed 'Best First'.

Re^3: Understanding a portion on the Perlretut
by Corion (Patriarch) on Dec 09, 2015 at 13:33 UTC

I linked to perlretut. Going there, I find:

The naive regexp
    ...
[download]
doesn't work; it may match a TGA , but there is no guarantee that the match is aligned with codon boundaries, e.g., the substring GTT GAA gives a match. A better solution is
    while ($dna =~ /(\w\w\w)*?TGA/g) { # note the minimal *?
    print "Got a TGA stop codon at position ", pos $dna, "\n";
    }
[download]
which prints
    Got a TGA stop codon at position 18
    Got a TGA stop codon at position 23
[download]
Position 18 is good, but position 23 is bogus. What happened?

Maybe it was too obvious for me, but a Codon is a nucleotide triplet.

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom